Search Results

You are looking at 1 - 10 of 18 items for

  • Author or Editor: Daniel Tonetti x
Clear All Modify Search
Free access

Daniel Tonetti, Jagdish Bhatnagar and L. Dade Lunsford

Object

The design of the Leksell Gamma Knife Perfexion facilitates stereotactic radiosurgery (SRS) on cervical spine targets provided that the target itself is located superior to the standard G stereotactic head frame base ring and does not move. This study was designed to measure potential deviations of targets in the upper cervical spine while using the currently available Leksell Coordinate Frame G.

Methods

A commercially available skull-and–cervical spine model was adapted for SRS using the Leksell Gamma Knife Perfexion. The Leksell Coordinate Frame G was attached to the model, and both CT and fluoroscopic imaging were performed to determine the potential for target deviation at standard Gamma Knife treatment angles of 70°, 90°, and 110°. In addition, target deviations observed at various heights of the patient positioning table were analyzed using a pair of orthogonal fluoroscopic images obtained at a standard 90° gamma angle and compared with target position as it relates to a reference bed height of 4.5 cm.

Results

An examination of multiple radiopaque targets embedded in or affixed to the model showed target deviations ranging from as low as 3.53 mm at the medial occiput–C1 junction to 15.56 mm at the C3–4 level during 70° extension. Target deviations at 110° flexion relative to targets on a 90° CT scan included deviations ranging from 0.58 mm at the medial occiput–C1 junction to 13.32 mm at the medial C3–4 level.

Relative to targets observed at the Perfexion table height of 4.5 cm, target deviation at a table height of 3 cm varied from 0.44 to 5.26 mm. At a table height of 5.5 cm, target deviation varied from 0.44 to 3.60 mm, and at a maximum height of 5.8 cm, target deviation varied from 0.62 to 4.30 mm.

Conclusions

Target deviation grossly exceeded clinical tolerance and was greater the farther the distance between the cranial base and the cervical spine target. Simple and reproducible methods that allow SRS centers to immobilize the patient's cervical spine using the currently available model G head frame are necessary to increase the range of targets that can be treated safely using the Leksell Gamma Knife Perfexion.

Restricted access

Daniel A. Tonetti, William J. Ares, David O. Okonkwo and Paul A. Gardner

OBJECTIVE

Large interhemispheric subdural hematomas (iSDHs) causing falx syndrome are rare; therefore, a paucity of data exists regarding the outcomes of contemporary management of iSDH. There is a general consensus among neurosurgeons that large iSDHs with neurological deficits represent a particular treatment challenge with generally poor outcomes. Thus, radiological and clinical outcomes of surgical and nonsurgical management for iSDH bear further study, which is the aim of this report.

METHODS

A prospectively collected, single-institution trauma database was searched for patients with isolated traumatic iSDH causing falx syndrome in the period from January 2008 to January 2018. Information on demographic and radiological characteristics, serial neurological examinations, clinical and radiological outcomes, and posttreatment complications was collected and tallied. The authors subsequently dichotomized patients by management strategy to evaluate clinical outcome and 30-day survival.

RESULTS

Twenty-five patients (0.4% of those with intracranial injuries, 0.05% of those with trauma) with iSDH and falx syndrome represented the study cohort. The average age was 73.4 years, and most patients (23 [92%] of 25) were taking anticoagulants or antiplatelet medications. Six patients were managed nonoperatively, and 19 patients underwent craniotomy for iSDH evacuation; of the latter patients, 17 (89.5%) had improvement in or resolution of motor deficits postoperatively. There were no instances of venous infarction, reaccumulation, or infection after evacuation. In total, 9 (36%) of the 25 patients died within 30 days, including 6 (32%) of the 19 who had undergone craniotomy and 3 (50%) of the 6 who had been managed nonoperatively. Patients who died within 30 days were significantly more likely to experience in-hospital neurological deterioration prior to surgery (83% vs 15%, p = 0.0095) and to be comatose prior to surgery (100% vs 23%, p = 0.0031). The median modified Rankin Scale score of surgical patients who survived hospitalization (13 patients) was 1 at a mean follow-up of 22.1 months.

CONCLUSIONS

iSDHs associated with falx syndrome can be evacuated safely and effectively, and prompt surgical evacuation prior to neurological deterioration can improve outcomes. In this study, craniotomy for iSDH evacuation proved to be a low-risk strategy that was associated with generally good outcomes, though appropriately selected patients may fare well without evacuation.

Free access

William J. Ares, Brian T. Jankowitz, Daniel A. Tonetti, Bradley A. Gross and Ramesh Grandhi

OBJECTIVE

Penetrating cerebrovascular injury (PCVI) is a subset of traumatic brain injury (TBI) comprising a broad spectrum of cerebrovascular pathology, including traumatic pseudoaneurysms, direct arterial injury, venous sinus stenosis or occlusion, and traumatic dural arteriovenous fistulas. These can result in immediate or delayed vascular injury and consequent neurological morbidity. Current TBI guidelines recommend cerebrovascular imaging for detection, but there is no consensus on the optimum modality. The aim of this retrospective cohort study was to compare CT angiography (CTA) and digital subtraction angiography (DSA) for the diagnosis of PCVI.

METHODS

The records of all patients presenting to two level I trauma centers in the United States between January 2010 and July 2016 with penetrating head or neck trauma were reviewed. Only those who had undergone both CTA and DSA were included. Clinical and neuroimaging data were collected, and PCVIs were stratified using a modified Biffl grading scheme. DSA and CTA results were then compared.

RESULTS

Of 312 patients with penetrating trauma over the study period, 56 patients (91% male, mean age 32 years) with PCVI met inclusion criteria and constituted the study cohort. The mechanism of injury was a gunshot wound in 86% (48/56) of patients. Twenty-four (43%) patients had sustained an angiographically confirmed arterial or venous injury. Compared with DSA as the gold standard, CTA had a sensitivity and specificity of 72% and 63%, respectively, for identifying PCVI. CTA had a positive predictive value of 61% and negative predictive value of 70%. Seven patients (13%) required immediate endovascular treatment of PCVI; in 3 (43%) of these patients, the injury was not identified on CTA. Twenty-two patients (39%) underwent delayed DSA an average of 25 days after injury; 2 (9%) of these patients were found to harbor new pathological conditions requiring treatment.

CONCLUSIONS

In this retrospective analysis of PCVI at two large trauma centers, CTA demonstrated low sensitivity, specificity, and positive and negative predictive values for the diagnosis of PCVI. These findings suggest that DSA provides better accuracy than CTA in the diagnosis of both immediate and delayed PCVI and should be considered for patients experiencing penetrating head or neck trauma.

Restricted access

Ali Kooshkabadi, L. Dade Lunsford, Daniel Tonetti, John C. Flickinger and Douglas Kondziolka

Object

The surgical management of disabling tremor has gained renewed vigor with the availability of deep brain stimulation. However, in the face of an aging population of patients with increasing surgical comorbidities, noninvasive approaches for tremor management are needed. The authors' purpose was to study the technique and results of stereotactic radiosurgery performed in the era of MRI targeting.

Methods

The authors evaluated outcomes in 86 patients (mean age 71 years; number of procedures 88) who underwent a unilateral Gamma Knife thalamotomy (GKT) for tremor during a 15-year period that spanned the era of MRI-based target selection (1996–2011). Symptoms were related to essential tremor in 48 patients (19 age ≥ 80 years and 3 age ≥ 90 years), Parkinson disease in 27 patients (11 age ≥ 80 years [1 patient underwent bilateral procedures]), and multiple sclerosis in 11 patients (1 patient underwent bilateral procedures). A single 4-mm isocenter was used to deliver a maximum dose of 140 Gy to the posterior-inferior region of the nucleus ventralis intermedius. The Fahn-Tolosa-Marin clinical tremor rating scale was used to grade tremor, handwriting, and ability to drink. The median follow-up was 23 months.

Results

The mean tremor score was 3.28 ± 0.79 before and 1.81 ± 1.15 after (p < 0.0001) GKT; the mean handwriting score was 2.78 ± 0.82 and 1.62 ± 1.04, respectively (p < 0.0001); and the mean drinking score was 3.14 ± 0.78 and 1.80 ± 1.15, respectively (p < 0.0001). After GKT, 57 patients (66%) showed improvement in all 3 scores, 11 patients (13%) in 2 scores, and 2 patients (2%) in just 1 score. In 16 patients (19%) there was a failure to improve in any score. Two patients developed a temporary contralateral hemiparesis, 1 patient noted dysphagia, and 1 sustained facial sensory loss.

Conclusions

Gamma Knife thalamotomy in the MRI era was a safe and effective noninvasive surgical strategy for medically refractory tremor in the elderly or those with contraindications to deep brain stimulation or stereotactic radiofrequency (thermal) thalamotomy.

Free access

Daniel Tonetti, Hideyuki Kano, Gregory Bowden, John C. Flickinger and L. Dade Lunsford

Object

The presentation for patients with arteriovenous malformations (AVMs) is often intracranial hemorrhage; for women, this frequently occurs during the prime childbearing years. Although previous studies have addressed the risk for AVM hemorrhage during pregnancy, such studies have not assessed the risk for hemorrhage among women who become pregnant during the latency interval between stereotactic radiosurgery (SRS) and documented obliteration of the lesion. The authors sought to evaluate the risk for hemorrhage in patients who become pregnant during the latency interval after SRS.

Methods

This single-institution retrospective analysis reviewed the authors' experience with Gamma Knife SRS during 1987–2012. During this time, 253 women of childbearing age (median age 30 years, range 15–40 years) underwent SRS for intracranial AVM. The median target volume was 3.9 cm3 (range 0.1–27.1 cm3), and the median marginal dose was 20 Gy (range 14–38 Gy). For all patients, the date of AVM obliteration was recorded and the latency interval was calculated. Information about subsequent pregnancies and/or bleeding events during the latency interval was retrieved from the medical records and supplemented by telephone contact.

Results

AVM obliteration was confirmed by MRI or angiography at a median follow-up time of 39.3 months (range 10–174 months). There were 828.7 patient-years of follow-up within the latency interval between SRS and the date of confirmed AVM obliteration. Among nonpregnant women, 20 hemorrhages occurred before AVM obliteration, yielding an annual hemorrhage rate of 2.5% for nonpregnant women during the latency interval. Among women who became pregnant during the latency interval, 2 hemorrhages occurred over the course of 18 pregnancies, yielding an annual hemorrhage rate of 11.1% for women who become pregnant during the latency interval. For the 2 pregnant patients who experienced hemorrhage, the bleeding occurred during the first trimester of pregnancy.

Conclusions

The authors present the first series of data for women with intracranial AVMs who became pregnant during the latency interval after SRS. Hemorrhage during the latency interval occurred at an annual rate of 2.5% for nonpregnant women and 11.1% for pregnant women. The data suggest that pregnancy might be a risk factor for AVM hemorrhage during the interval between SRS and AVM obliteration. However, this suggestion is not statistically significant because only 18 patients in the study population became pregnant during the latency interval. To mitigate any increased risk for hemorrhage, patients should consider deferring pregnancy until treatment conclusion and AVM obliteration.

Full access

Seyed H. Mousavi, Ajay Niranjan, Berkcan Akpinar, Marshall Huang, Hideyuki Kano, Daniel Tonetti, John C. Flickinger and L. Dade Lunsford

OBJECTIVE

In the era of MRI, vestibular schwannomas are often recognized when patients still have excellent hearing. Besides success in tumor control rate, hearing preservation is a main goal in any procedure for management of this population. The authors evaluated whether modified auditory subclassification prior to radiosurgery could predict long-term hearing outcome in this population.

METHODS

The authors reviewed a quality assessment registry that included the records of 1134 vestibular schwannoma patients who had undergone stereotactic radiosurgery during a 15-year period (1997–2011). The authors identified 166 patients who had Gardner-Robertson Class I hearing prior to stereotactic radiosurgery. Fifty-three patients were classified as having Class I-A (no subjective hearing loss) and 113 patients as Class I-B (subjective hearing loss). Class I-B patients were further stratified into Class I-B1 (pure tone average ≤ 10 dB in comparison with the contralateral ear; 56 patients), and I-B2 (> 10 dB compared with the normal ear; 57 patients). At a median follow-up of 65 months, the authors evaluated patients' hearing outcomes and tumor control.

RESULTS

The median pure tone average elevations after stereotactic radiosurgery were 5 dB, 13.5 dB, and 28 dB in Classes I-A, I-B1, and I-B2, respectively. The median declines in speech discrimination scores after stereotactic radiosurgery were 0% for Class I-A (p = 0.33), 8% for Class I-B1 (p < 0.0001), and 40% for Class I-B2 (p < 0.0001). Serviceable hearing preservation rates were 98%, 73%, and 33% for Classes I-A, I-B1, and I-B2, respectively. Gardner-Robertson Class I hearing was preserved in 87%, 43%, and 5% of patients in Classes I-A, I-B1, and I-B2, respectively.

CONCLUSIONS

Long-term hearing preservation was significantly better if radiosurgery was performed prior to subjective hearing loss. In patients with subjective hearing loss, the difference in pure tone average between the affected ear and the unaffected ear was an important factor in long-term hearing preservation.

Full access

Kyung-Jae Park, Hideyuki Kano, Aditya Iyer, Xiaomin Liu, Daniel A. Tonetti, Craig Lehocky, Andrew Faramand, Ajay Niranjan, John C. Flickinger, Douglas Kondziolka and L. Dade Lunsford

OBJECTIVE

The authors of this study evaluate the long-term outcomes of stereotactic radiosurgery (SRS) for cavernous sinus meningioma (CSM).

METHODS

The authors retrospectively assessed treatment outcomes 5–18 years after SRS in 200 patients with CSM. The median patient age was 57 years (range 22–83 years). In total, 120 (60%) patients underwent Gamma Knife SRS as primary management, 46 (23%) for residual tumors, and 34 (17%) for recurrent tumors after one or more surgical procedures. The median tumor target volume was 7.5 cm3 (range 0.1–37.3 cm3), and the median margin dose was 13.0 Gy (range 10–20 Gy).

RESULTS

Tumor volume regressed in 121 (61%) patients, was unchanged in 49 (25%), and increased over time in 30 (15%) during a median imaging follow-up of 101 months. Actuarial tumor control rates at the 5-, 10-, and 15-year follow-ups were 92%, 84%, and 75%, respectively. Of the 120 patients who had undergone SRS as a primary treatment (primary SRS), tumor progression was observed in 14 (11.7%) patients at a median of 48.9 months (range 4.8–120.0 months) after SRS, and actuarial tumor control rates were 98%, 93%, 85%, and 85% at the 1-, 5-, 10-, and 15-year follow-ups post-SRS. A history of tumor progression after microsurgery was an independent predictor of an unfavorable response to radiosurgery (p = 0.009, HR = 4.161, 95% CI 1.438–12.045). Forty-four (26%) of 170 patients who had presented with at least one cranial nerve (CN) deficit improved after SRS. Development of new CN deficits after initial microsurgical resection was an unfavorable factor for improvement after SRS (p = 0.014, HR = 0.169, 95% CI 0.041–0.702). Fifteen (7.5%) patients experienced permanent CN deficits without evidence of tumor progression at a median onset of 9 months (range 2.3–85 months) after SRS. Patients with larger tumor volumes (≥ 10 cm3) were more likely to develop permanent CN complications (p = 0.046, HR = 3.629, 95% CI 1.026–12.838). Three patients (1.5%) developed delayed pituitary dysfunction after SRS.

CONCLUSIONS

This long-term study showed that Gamma Knife radiosurgery provided long-term tumor control for most patients with CSM. Patients who underwent SRS for progressive tumors after prior microsurgery had a greater chance of tumor growth than the patients without prior surgery or those with residual tumor treated after microsurgery.

Restricted access

Eric Reseland, Nitin Agarwal, Michael M. McDowell, Jeremy G. Stone, Daniel A. Tonetti, Issam A. Awad, Charles J. Hodge, Karen S. Koenig, Allan H. Friedman and Robert M. Friedlander

Restricted access

Greg Bowden, Hideyuki Kano, Daniel Tonetti, Ajay Niranjan, John Flickinger and L. Dade Lunsford

Object

Arteriovenous malformations (AVMs) of the posterior fossa have an aggressive natural history and propensity for hemorrhage. Although the cerebellum accounts for the majority of the posterior fossa volume, there is a paucity of stereotactic radiosurgery (SRS) outcome data for AVMs of this region. The authors sought to evaluate the long-term outcomes and risks of cerebellar AVM radiosurgery.

Methods

This single-institution retrospective analysis reviewed the authors' experience with Gamma Knife surgery during the period 1987–2007. During this time 64 patients (median age 47 years, range 8–75 years) underwent SRS for a cerebellar AVM. Forty-seven patients (73%) presented with an intracranial hemorrhage. The median target volume was 3.85 cm3 (range 0.2–12.5 cm3), and the median marginal dose was 21 Gy (range 15–25 Gy).

Results

Arteriovenous malformation obliteration was confirmed by MRI or angiography in 40 patients at a median follow-up of 73 months (range 4–255 months). The actuarial rates of total obliteration were 53% at 3 years, 69% at 4 years, and 76% at 5 and 10 years. Elevated obliteration rates were statistically higher in patients who underwent AVM SRS without prior embolization (p = 0.005). A smaller AVM volume was also associated with a higher rate of obliteration (p = 0.03). Four patients (6%) sustained a hemorrhage during the latency period and 3 died. The cumulative rates of AVM hemorrhage after SRS were 6% at 1, 5, and 10 years. This correlated with an overall annual hemorrhage rate of 2.0% during the latency interval. One patient experienced a hemorrhage 9 years after confirmed MRI and angiographic obliteration. A permanent neurological deficit due to adverse radiation effects developed in 1 patient (1.6%) and temporary complications were seen in 2 additional patients (3.1%).

Conclusions

Stereotactic radiosurgery proved to be most effective for patients with smaller and previously nonembolized cerebellar malformations. Hemorrhage during the latency period occurred at a rate of 2.0% per year until obliteration occurred.

Full access

Hideyuki Kano, John C. Flickinger, Aya Nakamura, Rachel C. Jacobs, Daniel A. Tonetti, Craig Lehocky, Kyung-Jae Park, Huai-che Yang, Ajay Niranjan and L. Dade Lunsford

OBJECTIVE

The management of large-volume arteriovenous malformations (AVMs) with stereotactic radiosurgery (SRS) remains challenging. The authors retrospectively tested the hypothesis that AVM obliteration rates can be improved by increasing the percentage volume of an AVM that receives a minimal threshold dose of radiation.

METHODS

In 1992, the authors prospectively began to stage anatomical components in order to deliver higher single doses to AVMs > 15 cm3 in volume. Since that time 60 patients with large AVMs have undergone volume-staged SRS (VS-SRS). The median interval between the first stage and the second stage was 4.5 months (2.8–13.8 months). The median target volume was 11.6 cm3 (range 4.3–26 cm3) in the first-stage SRS and 10.6 cm3 (range 2.8–33.7 cm3) in the second-stage SRS. The median margin dose was 16 Gy (range 13–18 Gy) for both SRS stages.

RESULTS

AVM obliteration after the initial two staged volumetric SRS treatments was confirmed by MRI alone in 4 patients and by angiography in 11 patients at a median follow-up of 82 months (range 0.4–206 months) after VS-SRS. The post–VS-SRS obliteration rates on angiography were 4% at 3 years, 13% at 4 years, 23% at 5 years, and 27% at 10 years. In multivariate analysis, only ≥ 20-Gy volume coverage was significantly associated with higher total obliteration rates confirmed by angiography. When the margin dose is ≥ 17 Gy and the 20-Gy SRS volume included ≥ 63% of the total target volume, the angiographically confirmed obliteration rates increased to 61% at 5 years and 70% at 10 years.

CONCLUSIONS

The outcomes of prospective VS-SRS for large AVMs can be improved by prescribing an AVM margin dose of ≥ 17 Gy and adding additional isocenters so that ≥ 63% of the internal AVM dose receives more than 20 Gy.